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OS/2 Shareware BBS: 10 Tools
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snip9707.zip
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ISFOPEN.C
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C/C++ Source or Header
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1997-07-05
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956b
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47 lines
/* +++Date last modified: 05-Jul-1997 */
/*
** Find out if a FILE * is valid
**
** public domain demo by Bob Stout
*/
#include "dosfiles.h"
#ifdef __TURBOC__
#define STREAM_BUF _streams
#define FCNT FOPEN_MAX
#define FLAG flags
#elif defined(__WATCOMC__)
#define STREAM_BUF __iob
#define FCNT _NFILES
#define FLAG _flag
#else /* MSC, ZTC++ */
#define STREAM_BUF _iob
#define FCNT _NFILE
#define FLAG _flag
#endif
int isfopen(FILE *fp)
{
int i;
for (i = 0; i < FCNT; ++i)
{
if (0 != STREAM_BUF[i].FLAG && fp == &STREAM_BUF[i])
return True_;
}
return False_;
}
#ifdef TEST
main()
{
printf("stdout is%s valid\n", isfopen(stdout) ? "":" not");
printf("buffer #10 is%s valid\n", isfopen(&STREAM_BUF[9]) ? "":" not");
return 0;
}
#endif /*TEST */