tmpnam, _wtmpnam

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Header File

stdio.h

Category

Input/output Routines

Prototype

char *tmpnam(char *s);

wchar_t *_wtmpnam(wchar_t *s);

Description

Creates a unique file name.

tmpnam creates a unique file name, which can safely be used as the name of a temporary file. tmpnam generates a different string each time you call it, up to TMP_MAX times. TMP_MAX is defined in stdio.h as 65,535.

The parameter to tmpnam, s, is either null or a pointer to an array of at least L_tmpnam characters. L_tmpnam is defined in stdio.h. If s is NULL, tmpnam leaves the generated temporary file name in an internal static object and returns a pointer to that object. If s is not NULL, tmpnam overwrites the internal static object and places its result in the pointed-to array, which must be at least L_tmpnam characters long, and returns s.

If you do create such a temporary file with tmpnam, it is your responsibility to delete the file name (for example, with a call to remove). It is not deleted automatically. (tmpfile does delete the file name.)

Return Value

If s is null, tmpnam returns a pointer to an internal static object. Otherwise, tmpnam returns s.

Example

#include <stdio.h>
int main(void)
{
   char name[13];
   tmpnam(name);
   printf("Temporary name: %s\n", name);
   return 0;
}

Portability

	POSIX	Win32	ANSI C	ANSI C++
tmpnam	+	+	+	+
_wtmpnam		+