MPATROL

NAME

SYNOPSIS

#include <mpatrol.h>

void *malloc(size_t size);
void *calloc(size_t nelem, size_t size);
void *memalign(size_t align, size_t size);
void *valloc(size_t size);
void *pvalloc(size_t size);
char *strdup(const char *str);
char *strndup(const char *str, size_t size);
char *strsave(const char *str);
char *strnsave(const char *str, size_t size);
void *realloc(void *ptr, size_t size);
void *recalloc(void *ptr, size_t nelem, size_t size);
void *expand(void *ptr, size_t size);
void free(void *ptr);
void cfree(void *ptr, size_t nelem, size_t size);

void *operator new(size_t size);
void *operator new[](size_t size);
void operator delete(void *ptr);
void operator delete[](void *ptr);
void (*set_new_handler(void (*func)(void)))(void);

void *memset(void *ptr, int byte, size_t size);
void bzero(void *ptr, size_t size);
void *memccpy(void *dest, const void *src, int byte,
              size_t size);
void *memcpy(void *dest, const void *src, size_t size);
void *memmove(void *dest, const void *src, size_t size);
void bcopy(const void *src, void *dest, size_t size);
int memcmp(const void *ptr1, const void *ptr2,
           size_t size);
int bcmp(const void *ptr1, const void *ptr2, size_t size);
void *memchr(const void *ptr, int byte, size_t size);
void *memmem(const void *ptr1, size_t size1,
             const void *ptr2, size_t size2);

int __mp_info(const void *ptr, __mp_allocinfo *info);
int __mp_printinfo(const void *ptr);
void __mp_memorymap(int stats);
void __mp_summary(void);
void __mp_check(void);
void (*__mp_prologue(void (*func)(const void *, size_t)))
     (const void *, size_t);
void (*__mp_epilogue(void (*func)(const void *)))
     (const void *);
void (*__mp_nomemory(void (*func)(void)))(void);

DESCRIPTION

All of the function definitions in mpatrol.h can be disabled by defining the NDEBUG preprocessor macro, which is the same macro used to control the behaviour of the assert function. If NDEBUG is defined then no macro redefinition of functions will take place and all special mpatrol library functions will evaluate to empty statements. It is intended that the NDEBUG preprocessor macro be defined in release builds.

All diagnostics are sent to the file mpatrol.log in the current directory by default but this can be changed at run-time. Additional configuration options can also be changed at run-time by setting and altering the MPATROL_OPTIONS environment variable. See ENVIRONMENT below for more details.

Details of memory allocations and free memory are stored internally as a tree structure for speed and also to allow the best fit allocation algorithm to be used. This also enables the library to perform intelligent resizing of memory allocations and can be used to quickly determine if an address has been allocated on the heap.

On systems that support memory protection, the library attempts to detect any illegal memory accesses and display as much information as it can obtain about the address in question and where the illegal memory access occurred.

Stack traceback information for every memory allocation is available on some supported platforms, which is useful for determining exactly where a memory allocation was performed or for adding meaning to tracing. Symbol names are read from the executable file and also possibly from any required shared libraries, and if the USEDEBUG option is used and is available then the debugging section in the executable file will be read to determine additional source-level information.

Memory allocation profiling is supported, with statistics about every memory allocation and deallocation that was made during the execution of a program being written to a file at program termination if the PROF option is used. The information stored in this file can then be used by the mprof command to display various tables summarising the memory allocation behaviour of the program that produced it.  

FUNCTIONS

malloc

Allocates size uninitialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be suitably aligned for casting to any type and can be used to store data of up to size bytes in length. If size is 0 then the memory allocated will be implicitly rounded up to 1 byte. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc.

calloc

Allocates nelem elements of size zero-initialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be suitably aligned for casting to any type and can be used to store data of up to nelem * size bytes in length. If nelem * size is 0 then the amount of memory allocated will be implicitly rounded up to 1 byte. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc.

memalign

Allocates size uninitialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be aligned to align bytes and can be used to store data of up to size bytes in length. If align is zero then the default system alignment will be used. If align is not a power of two then it will be rounded up to the nearest power of two. If align is greater than the system page size then it will be truncated to that value. If size is 0 then the memory allocated will be implicitly rounded up to 1 byte. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc, although the latter will not guarantee the preservation of alignment.

valloc

Allocates size uninitialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be aligned to the system page size and can be used to store data of up to size bytes in length. If size is 0 then the memory allocated will be implicitly rounded up to 1 byte. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc, although the latter will not guarantee the preservation of alignment.

pvalloc

Allocates size uninitialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be aligned to the system page size and can be used to store data of up to size bytes in length. If size is 0 then the memory allocated will be implicitly rounded up to 1 page, otherwise size will be implicitly rounded up to a multiple of the system page size. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc, although the latter will not guarantee the preservation of alignment.

strdup

Allocates exactly enough memory from the heap to duplicate str (including the terminating nul character) and returns a pointer to the first byte of the allocation after copying str to the newly-allocated memory. The pointer returned will have no alignment constraints and can be used to store character data up to the length of str. If str is NULL then the null pointer will be returned. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc.

strndup

Allocates exactly enough memory from the heap to duplicate str (including the terminating nul character) and returns a pointer to the first byte of the allocation after copying str to the newly-allocated memory. The pointer returned will have no alignment constraints and can be used to store character data up to the length of str. If str is NULL then the null pointer will be returned. If the length of str is greater than size then only size characters will be allocated and copied, with one additional byte for the nul character. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc. This function is available for backwards compatibility with older C libraries and should not be used in new code.

strsave

Allocates exactly enough memory from the heap to duplicate str (including the terminating nul character) and returns a pointer to the first byte of the allocation after copying str to the newly-allocated memory. The pointer returned will have no alignment constraints and can be used to store character data up to the length of str. If str is NULL then the null pointer will be returned. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc. This function is available for backwards compatibility with older C libraries and should not be used in new code.

strnsave

Allocates exactly enough memory from the heap to duplicate str (including the terminating nul character) and returns a pointer to the first byte of the allocation after copying str to the newly-allocated memory. The pointer returned will have no alignment constraints and can be used to store character data up to the length of str. If str is NULL then the null pointer will be returned. If the length of str is greater than size then only size characters will be allocated and copied, with one additional byte for the nul character. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free or reallocated with realloc. This function is available for backwards compatibility with older C libraries and should not be used in new code.

realloc

Resizes the memory allocation beginning at ptr to size bytes and returns a pointer to the first byte of the new allocation after copying ptr to the newly-allocated memory, which will be truncated if size is smaller than the original allocation. The pointer returned will be suitably aligned for casting to any type and can be used to store data of up to size bytes in length. If ptr is NULL then the call will be equivalent to malloc. If size is 0 then the existing memory allocation will be freed and the null pointer will be returned. If size is greater than the original allocation then the extra space will be filled with uninitialised bytes. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free and can be reallocated again with realloc.

recalloc

Resizes the memory allocation beginning at ptr to nelem elements of size bytes and returns a pointer to the first byte of the new allocation after copying ptr to the newly-allocated memory, which will be truncated if nelem * size is smaller than the original allocation. The pointer returned will be suitably aligned for casting to any type and can be used to store data of up to nelem * size bytes in length. If ptr is NULL then the call will be equivalent to calloc. If nelem * size is 0 then the existing memory allocation will be freed and the null pointer will be returned. If nelem * size is greater than the original allocation then the extra space will be filled with zero-initialised bytes. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free and can be reallocated again with realloc. This function is available for backwards compatibility with older C libraries and calloc and should not be used in new code.

expand

Attempts to resize the memory allocation beginning at ptr to size bytes and either returns ptr if there was enough space to resize it, or NULL if the block could not be resized for a particular reason. If ptr is NULL then the call will be equivalent to malloc. If size is 0 then the existing memory allocation will be freed and the NULL pointer will be returned. If size is greater than the original allocation then the extra space will be filled with uninitialised bytes and if size is less than the original allocation then the memory block will be truncated. If there is not enough space in the heap then the NULL pointer will be returned and errno will be set to ENOMEM. The allocated memory must be deallocated with free and can be reallocated again with realloc. This function is available for backwards compatibility with older C libraries and should not be used in new code.

free

Frees the memory allocation beginning at ptr so the memory can be reused by another call to allocate memory. If ptr is NULL then no memory will be freed. All of the previous contents will be destroyed.

cfree

Frees the memory allocation beginning at ptr so the memory can be reused by another call to allocate memory. If ptr is NULL then no memory will be freed. All of the previous contents will be destroyed. The nelem and size parameters are ignored in this implementation. This function is available for backwards compatibility with older C libraries and calloc and should not be used in new code.

The following 5 functions are available as replacements for existing C++ library functions, but the replacements in mpatrol.h will only be used if the MP_NOCPLUSPLUS preprocessor macro is not defined. To use these you must include mpatrol.h before all other header files, although on UNIX and Windows platforms (and AmigaOS when using gcc) they will be used anyway, albeit with slightly less tracing information:

operator new

Allocates size uninitialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be suitably aligned for casting to any type and can be used to store data of up to size bytes in length. If size is 0 then the memory allocated will be implicitly rounded up to 1 byte. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM - no exceptions will be thrown. The allocated memory must be deallocated with operator delete.

operator new[]

Allocates size uninitialised bytes from the heap and returns a pointer to the first byte of the allocation. The pointer returned will be suitably aligned for casting to any type and can be used to store data of up to size bytes in length. If size is 0 then the memory allocated will be implicitly rounded up to 1 byte. If there is not enough space in the heap then the null pointer will be returned and errno will be set to ENOMEM - no exceptions will be thrown. The allocated memory must be deallocated with operator delete[].

operator delete

Frees the memory allocation beginning at ptr so the memory can be reused by another call to allocate memory. If ptr is NULL then no memory will be freed. All of the previous contents will be destroyed. This function must only be used with memory allocated by operator new.

operator delete[]

Frees the memory allocation beginning at ptr so the memory can be reused by another call to allocate memory. If ptr is NULL then no memory will be freed. All of the previous contents will be destroyed. This function must only be used with memory allocated by operator new[].

set_new_handler

Installs a low-memory handler specifically for use with operator new and operator new[] and returns a pointer to the previously installed handler, or the null pointer if no handler had been previously installed. This will be called repeatedly by both functions when they would normally return NULL, and this loop will continue until they manage to allocate the requested space. The default low-memory handler for the C++ operators will terminate the program and write an out of memory message to the log file. Note that this function is equivalent to __mp_nomemory and will replace the handler installed by that function.

The following 10 functions are available as replacements for existing C library memory operation functions. To use these you must include mpatrol.h before all other header files, although on UNIX and Windows platforms (and AmigaOS when using gcc) they will be used anyway, albeit with slightly less tracing information:

memset

Writes size bytes of value byte to the memory location beginning at ptr and returns ptr. If size is 0 then no bytes will be written. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be written.

bzero

Writes size zero bytes to the memory location beginning at ptr. If size is 0 then no bytes will be written. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be written. This function is available for backwards compatibility with older C libraries and should not be used in new code.

memccpy

Copies size bytes from src to dest and returns NULL, or copies the number of bytes up to and including the first occurrence of byte if byte exists within the specified range and returns a pointer to the first byte after byte. If size is 0 or src is the same as dest then no bytes will be copied. The source and destination ranges should not overlap, otherwise a warning will be written to the log file. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be copied.

memcpy

Copies size bytes from src to dest and returns dest. If size is 0 or src is the same as dest then no bytes will be copied. The source and destination ranges should not overlap, otherwise a warning will be written to the log file. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be copied.

memmove

Copies size bytes from src to dest and returns dest. If size is 0 or src is the same as dest then no bytes will be copied. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be copied.

bcopy

Copies size bytes from src to dest. If size is 0 or src is the same as dest then no bytes will be copied. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be copied. This function is available for backwards compatibility with older C libraries and should not be used in new code.

memcmp

Compares size bytes from ptr1 and ptr2 and returns 0 if all of the bytes are identical, or returns the byte difference of the first differing bytes. If size is 0 or ptr1 is the same as ptr2 then no bytes will be compared. If the operation would read from an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be compared.

bcmp

Compares size bytes from ptr1 and ptr2 and returns 0 if all of the bytes are identical, or returns the byte difference of the first differing bytes. If size is 0 or ptr1 is the same as ptr2 then no bytes will be compared. If the operation would read from an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be compared. This function is available for backwards compatibility with older C libraries and should not be used in new code.

memchr

Searches up to size bytes in ptr for the first occurrence of byte and returns a pointer to it or NULL if no such byte occurs. If size is 0 then no bytes will be searched. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be searched.

memmem

Searches up to size1 bytes in ptr1 for the first occurrence of ptr2 (which is exactly size2 bytes in length) and returns a pointer to it or NULL if no such sequence of bytes occur. If size1 or size2 is 0 then no bytes will be searched. If the operation would affect an existing memory allocation in the heap but would straddle that allocation's boundaries then an error message will be generated in the log file and no bytes will be searched.

The following 8 functions are available as support routines for additional control and tracing in the mpatrol library. To use these you should include the mpatrol.h header file:

__mp_info

Obtains information about a specific memory allocation by placing statistics about ptr in info. If ptr does not belong to a previously allocated memory allocation then 0 will be returned, otherwise 1 will be returned and info will contain the following information:

 Field   Description

 block   Pointer to first byte of alloc.
 size    Size of alloc in bytes.
 type    Type of function which allocated memory.
 alloc   Allocation index.
 realloc Number of times reallocated.
 thread  Thread identifier.
 func    Function in which alloc took place.
 file    File in which alloc took place.
 line    Line number at which alloc took place.
 stack   Pointer to function call stack.
 freed   Indicates if alloc has been freed.

__mp_printinfo

Displays information about a specific memory allocation containing ptr to the standard error file stream. If ptr does not belong to a previously allocated memory allocation then 0 will be returned, otherwise 1 will be returned. This function is intended to be called from within a debugger.

__mp_memorymap

If stats is non-zero then the current statistics of the mpatrol library will be displayed. If the heap contains at least one allocated, freed or free block then a map of the current heap will also be displayed.

__mp_summary

Displays information about the current state of the mpatrol library, including its settings and any relevant statistics.

__mp_check

Forces the library to perform an immediate check of the overflow buffers of every memory allocation and to ensure that nothing has overwritten any free blocks.

__mp_prologue

Installs a prologue function to be called before any memory allocation, reallocation or deallocation function. This function will return a pointer to the previously installed prologue function, or the null pointer if no prologue function had been previously installed. The following arguments will be used to call the prologue function:

 Argument 1 Argument 2 Called by

 -1         size       malloc, etc.
 ptr        size       realloc, etc.
 ptr        -1         free, etc.
 ptr        -2         strdup, etc.

__mp_epilogue

Installs an epilogue function to be called after any memory allocation, reallocation or deallocation function. This function will return a pointer to the previously installed epilogue function, or the null pointer if no epilogue function had been previously installed. The following arguments will be used to call the epilogue function:

 Argument Called by

 ptr      malloc, realloc, strdup, etc.
 -1       free, etc.

__mp_nomemory

Installs a low-memory handler and returns a pointer to the previously installed handler, or the null pointer if no handler had been previously installed. This will be called once by C memory allocation functions, and repeatedly by C++ memory allocation functions, when they would normally return NULL. Note that this function is equivalent to set_new_handler and will replace the handler installed by that function.

LINKING

 Library        Reason

 -lmpatrol      To use this library.
 -lelf          If built with FORMAT=FORMAT_ELF32.
 -lbfd -liberty If built with FORMAT=FORMAT_BFD.
 -lpthread      If built with MP_THREADS_SUPPORT.

On UNIX platforms, if there were no calls to memory allocation functions before -lmpatrol appears on the link line then the mpatrol library will not be linked in. However, this can be overridden by placing -umalloc just before that point.

You may also wish to set your core file size limit to be zero before running any programs linked with the mpatrol library as the extra memory that the library uses can make such files much larger than normal, and if you are planning on using a symbolic debugger then you won't need the core files anyway.  

ENVIRONMENT

The syntax for options specified within the MPATROL_OPTIONS environment variable is OPTION or OPTION=VALUE, where OPTION is a keyword from the list below and VALUE is the setting for that option. If VALUE is numeric then it may be specified using binary, octal, decimal or hexadecimal notation, with binary notation beginning with either 0b or 0B. If VALUE is a character string containing spaces then it may be quoted using double quotes. No whitespace may appear between the = sign, but whitespace must appear between different options. Note that option keywords can be given in lowercase as well as uppercase, or a mixture of both.

ALLOCBYTE=unsigned integer

Specifies an 8-bit byte pattern with which to prefill newly-allocated memory. This can be used to detect the use of memory which has not been initialised after allocation. Note that this setting will not affect memory allocated with calloc or recalloc as these functions always prefill allocated memory with an 8-bit byte pattern of zero. Default value: ALLOCBYTE=0xFF.

ALLOCSTOP=unsigned integer

Specifies an allocation index at which to stop the program when it is being allocated. When the number of memory allocations reaches this number the program will be halted, and its state may be examined at that point by using a suitable debugger. Note that this setting will be ignored if its value is zero. Default value: ALLOCSTOP=0.

ALLOWOFLOW

Specifies that a warning rather than an error should be produced if any memory operation function overflows the boundaries of a memory allocation, and that the operation should still be performed. This option is provided for circumstances where it is desirable for the memory operation to be performed, regardless of whether it is erroneous or not.

AUTOSAVE=unsigned integer

Specifies the frequency at which to periodically write the profiling data to the profiling output file. When the total number of profiled memory allocations and deallocations is a multiple of this number then the current profiling information will be written to the profiling output file. This option can be used to instruct the mpatrol library to dump out any profiling information just before a fatal error occurs in a program, for example. Note that this setting will be ignored if its value is zero. Default value: AUTOSAVE=0.

CHECK=unsigned range

Specifies a range of allocation indices at which to check the integrity of free memory and overflow buffers. The range must be specified as no more than two unsigned integers separated by a dash. If numbers on either the left side or the right side of the dash are omitted then they will be assumed to be 0 and infinity respectively. A value of 0 on its own indicates that no such checking will ever be performed. This option can be used to speed up the execution speed of the library at the expense of checking. Default value: CHECK=-.

CHECKALL

Equivalent to the CHECKALLOCS, CHECKREALLOCS and CHECKFREES options specified together.

CHECKALLOCS

Checks that no attempt is made to allocate a block of memory of size zero. A warning will be issued for every such case.

CHECKFREES

Checks that no attempt is made to deallocate a NULL pointer. A warning will be issued for every such case.

CHECKREALLOCS

Checks that no attempt is made to reallocate a NULL pointer or resize an existing block of memory to size zero. Warnings will be issued for every such case.

DEFALIGN=unsigned integer

Specifies the default alignment for general-purpose memory allocations, which must be a power of two (and will be rounded up to the nearest power of two if it is not). The default alignment for a particular system is calculated at run-time.

FAILFREQ=unsigned integer

Specifies the frequency at which all memory allocations will randomly fail. For example, a value of 10 will mean that roughly 1 in 10 memory allocations will fail, but a value of 0 will disable all random failures. This option can be useful for stress-testing an application. Default value: FAILFREQ=0.

FAILSEED=unsigned integer

Specifies the random number seed which will be used when determining which memory allocations will randomly fail. A value of 0 will instruct the library to pick a random seed every time it is run. Any other value will mean that the random failures will be the same every time the program is run, but only as long as the seed stays the same. Default value: FAILSEED=0.

FREEBYTE=unsigned integer

Specifies an 8-bit byte pattern with which to prefill newly-freed memory. This can be used to detect the use of memory which has just been freed. It is also used internally to ensure that freed memory has not been overwritten. Note that the freed memory may be reused the next time a block of memory is allocated and so once memory has been freed its contents are not guaranteed to remain the same as the specified byte pattern. Default value: FREEBYTE=0x55.

FREESTOP=unsigned integer

Specifies an allocation index at which to stop the program when it is being freed. When the memory allocation with the specified allocation index is to be freed the program will be halted, and its state may be examined at that point using a suitable debugger. Note that this setting will be ignored if its value is zero. Default value: FREESTOP=0.

HELP

Displays a quick-reference option summary to the stderr file stream.

LARGEBOUND=unsigned integer

Specifies the limit in bytes up to which memory allocations should be classified as large allocations for profiling purposes. This limit must be greater than the small and medium bounds. Default value: LARGEBOUND=2048.

LIMIT=unsigned integer

Specifies the limit in bytes at which all memory allocations should fail if the total allocated memory should increase beyond this. This can be used to stress-test software to see how it behaves in low memory conditions. The internal memory used by the library itself will not be counted as part of the total heap size, but on some systems there may be a small amount of memory required to initialise the library itself. Note that this setting will be ignored if its value is zero. Default value: LIMIT=0.

LOGALL

Equivalent to the LOGALLOCS, LOGREALLOCS, LOGFREES and LOGMEMORY options specified together.

LOGALLOCS

Specifies that all memory allocations are to be logged and sent to the log file. Note that any memory allocations made internally by the library will not be logged.

LOGFILE=string

Specifies an alternative file in which to place all diagnostics from the mpatrol library. A filename of stderr will send all diagnostics to the stderr file stream and a filename of stdout will do the equivalent with the stdout file stream. Note that if a problem occurs while opening the log file or if any diagnostics require to be displayed before the log file has had a chance to be opened then they will be sent to the stderr file stream. Default value: LOGFILE=mpatrol.log

LOGFREES

Specifies that all memory deallocations are to be logged and sent to the log file. Note that any memory deallocations made internally by the library will not be logged.

LOGMEMORY

Specifies that all memory operations are to be logged and sent to the log file. These operations will be made by calls to functions such as memset and memcpy. Note that any memory operations made internally by the library will not be logged.

LOGREALLOCS

Specifies that all memory reallocations are to be logged and sent to the log file. Note that any memory reallocations made internally by the library will not be logged.

MEDIUMBOUND=unsigned integer

Specifies the limit in bytes up to which memory allocations should be classified as medium allocations for profiling purposes. This limit must be greater than the small bound but less than the large bound. Default value: MEDIUMBOUND=256.

NOFREE

Specifies that the mpatrol library should keep all reallocated and freed memory allocations. Such freed memory allocations will then be flagged as freed and can be used by the library to provide better diagnostics. However, as no system memory will ever be reused by the mpatrol library, this option can quickly lead to a shortage of available system memory for a process. Note that this option will always force a memory reallocation to return a pointer to newly-allocated memory, but the expand function will never be affected by this option.

NOPROTECT

Specifies that the mpatrol library's internal data structures should not be made read-only after every memory allocation reallocation or deallocation. This may significantly speed up execution but this will be at the expense of less safety if the program accidentally overwrites some of the library's internal data structures. Note that this option has no effect on systems that do not support memory protection.

OFLOWBYTE=unsigned integer

Specifies an 8-bit byte pattern with which to fill the overflow buffers of all memory allocations. This is used internally to ensure that nothing has been written beyond the beginning or the end of a block of allocated memory. Note that this setting will only have an effect if the OFLOWSIZE option is in use. Default value: OFLOWBYTE=0xAA.

OFLOWSIZE=unsigned integer

Specifies the size in bytes to use for all overflow buffers, which must be a power of two (and will be rounded up to the nearest power of two if it is not). This is used internally to ensure that nothing has been written beyond the beginning or the end of a block of allocated memory. Note that this setting specifies the size for only one of the overflow buffers given to each memory allocation; the other overflow buffer will have an identical size. No overflow buffers will be used if this setting is zero. Default value: OFLOWSIZE=0.

OFLOWWATCH

Specifies that watch point areas should be used for overflow buffers rather than filling with the overflow byte. This can significantly reduce the speed of program execution. Note that this option has no effect on systems that do not support watch point areas.

PAGEALLOC=LOWER|UPPER

Specifies that each individual memory allocation should occupy at least one page of virtual memory and should be placed at the lowest or highest point within these pages. This allows the library to place an overflow buffer of one page on either side of every memory allocation and write-protect these pages as well as all free and freed memory. Note that this option has no effect on systems that do not support memory protection, and is disabled by default on other systems as it can slow down the speed of program execution.

PRESERVE

Specifies that any reallocated or freed memory allocations should preserve their original contents. This option must be used with the NOFREE option and has no effect otherwise.

PROF

Specifies that all memory allocations and deallocations are to be profiled and sent to the profiling output file. Memory reallocations are treated as a memory deallocation immediately followed by a memory allocation.

PROFFILE=string

Specifies an alternative file in which to place all memory allocation profiling information from the mpatrol library. A filename of stderr will send this information to the stderr file stream and a filename of stdout will do the equivalent with the stdout file stream. Note that if a problem occurs while opening the profiling output file then the profiling information will be sent to the stderr file stream. Default value: PROFFILE=mpatrol.out.

PROGFILE=string

Specifies an alternative filename with which to locate the executable file containing the program's symbols. On most systems, the library will automatically be able to determine this filename, but on a few systems this option may have to be used before any or all symbols can be read.

REALLOCSTOP=unsigned integer

Specifies a reallocation index at which to stop the program when a memory allocation is being reallocated. If the ALLOCSTOP option is non-zero then the program will be halted when the allocation matching that allocation index is reallocated the specified number of times. Otherwise the program will be halted the first time any allocation is reallocated the specified number of times. Note that this setting will be ignored if its value is zero. Default value: REALLOCSTOP=0.

SAFESIGNALS

Instructs the library to save and replace certain signal handlers during the execution of library code and to restore them afterwards. This was the default behaviour in version 1.0 of the mpatrol library and was changed since some memory-intensive programs became very hard to interrupt using the keyboard, thus giving the impression that the program or system had hung.

SHOWALL

Equivalent to the SHOWFREED, SHOWUNFREED, SHOWMAP and SHOWSYMBOLS options specified together.

SHOWFREED

Specifies that a summary of all of the freed memory allocations should be displayed at the end of program execution. This option must be used in conjunction with the NOFREE option and this step will not be performed if an abnormal termination occurs or if there were no freed allocations.

SHOWMAP

Specifies that a memory map of the entire heap should be displayed at the end of program execution. This step will not be performed if an abnormal termination occurs or if the heap is empty.

SHOWSYMBOLS

Specifies that a summary of all of the function symbols read from the program's executable file should be displayed at the end of program execution. This step will not be performed if an abnormal termination occurs or if no symbols could be read from the executable file.

SHOWUNFREED

Specifies that a summary of all of the unfreed memory allocations should be displayed at the end of program execution. This step will not be performed if an abnormal termination occurs or if there are no unfreed allocations.

SMALLBOUND=unsigned integer

Specifies the limit in bytes up to which memory allocations should be classified as small allocations for profiling purposes. This limit must be greater than zero but less than the medium and large bounds. Default value: SMALLBOUND=32.

UNFREEDABORT=unsigned integer

Specifies the minimum number of unfreed allocations at which to abort the program just before program termination. A summary of all the allocations will be displayed on the standard error file stream before aborting. This option may be handy for use in batch tests as it can force tests to fail if they do not free up a minimum number of memory allocations. Note that this setting will be ignored if its value is zero. Default value: UNFREEDABORT=0.

USEDEBUG

Specifies that any debugging information in the executable file should be used to obtain additional source-level information. This option will only have an effect if the executable file contains a compiler-generated line number table and will be ignored if the mpatrol library was built to support an object file access library that cannot read line tables from object files.

USEMMAP

Specifies that the library should use mmap instead of sbrk to allocate system memory on UNIX platforms. This option should be used if there are problems when using the mpatrol library in combination with another malloc library which uses sbrk to allocate its memory. It is ignored on systems that do not support the mmap system call.

SEE ALSO

The mpatrol manual, reference card and FAQ.

http://www.cbmamiga.demon.co.uk/mpatrol/  

AUTHOR

COPYRIGHT

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details.

You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

Index

NAME

SYNOPSIS

DESCRIPTION

FUNCTIONS

LINKING

ENVIRONMENT

SEE ALSO

AUTHOR

COPYRIGHT