tempnam(3) [osf1 man page]
tmpnam(3) Library Functions Manual tmpnam(3) NAME
tmpnam, tempnam - Construct the name for a temporary file LIBRARY
Standard C Library (libc.so, libc.a) SYNOPSIS
#include <stdio.h> char *tmpnam( char *s); char *tempnam( const char *directory, const char *prefix); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: tmpnam(), tempnam(): XSH4.2 Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Specifies the address of an array of at least the number of bytes specified by L_tmpnam, a constant defined in the stdio.h header file. Points to the pathname of the directory in which the file is to be created. Points to an initial letter sequence with which the filename begins. The prefix parameter can be null, or it can point to a string of up to 5 bytes to be used as the beginning of the temporary file- name. DESCRIPTION
The tmpnam() and tempnam() functions generate filenames for temporary files. The tmpnam() function generates a filename using the pathname defined as P_tmpdir in the stdio.h header file. Files created using this function reside in a directory intended for temporary use, and their names are unique. It is the application's responsibility to use the unlink() function to remove the files when they are no longer needed. Between the time a filename is created and the file is opened, it is possible for some other process to create a file with the same name. This should not happen if that other process uses these functions or the mktemp() function, and if the filenames are chosen to make dupli- cation by other means unlikely. The tempnam() function allows you to control the choice of a directory. If the directory parameter is null or points to a string that is not a pathname for an appropriate directory, the pathname defined as P_tmpdir in the stdio.h header file is used. If that pathname is not accessible, /tmp is used. You can bypass the selection of a pathname by providing an environment variable, TMPDIR, in the user's environ- ment. The value of the TMPDIR variable is a pathname for the desired temporary file directory. The prefix parameter can be used to specify a prefix of up to 5 bytes for the temporary filename. NOTES
If the s parameter is null, the tmpnam() function places its result into an internal thread-specific buffer and returns a pointer to that area. Subsequent calls to this function from the same thread overwrite this buffer. The tmpnam() function generates a different filename each time it is called. [Tru64 UNIX] If tmpnam() is called more than TMP_MAX times by a single process, it starts recycling previously used names. RETURN VALUES
If the s parameter is null, tmpnam() function places its result into an internal thread-specific buffer and returns a pointer to that area. If the s parameter is not null, it is assumed to be the address of an array of at least the number of bytes specified by the L_tmpnam con- stant. The tmpnam() function places its results into that array and returns the value of the s parameter. Upon successful completion, the tempnam() function returns a pointer to the generated pathname, suitable for use in a subsequent call to the free() function. Otherwise, null is returned and errno is set to indicate the error. ERRORS
If the tempnam() function fails, errno may be set to the following value: Insufficient storage space is available. RELATED INFORMATION
Functions: fopen(3), free(3), malloc(3), mktemp(3), open(2), tmpfile(3), unlink(2) Standards: standards(5) delim off tmpnam(3)
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tmpnam(3C) Standard C Library Functions tmpnam(3C) NAME
tmpnam, tmpnam_r, tempnam - create a name for a temporary file SYNOPSIS
#include <stdio.h> char *tmpnam(char *s); char *tmpnam_r(char *s); char *tempnam(const char *dir, const char *pfx); DESCRIPTION
These functions generate file names that can be used safely for a temporary file. tmpnam() The tmpnam() function always generates a file name using the path prefix defined as P_tmpdir in the <stdio.h> header. On Solaris systems, the default value for P_tmpdir is /var/tmp. If s is NULL, tmpnam() leaves its result in a thread-specific data area and returns a pointer to that area. The next call to tmpnam() by the same thread will destroy the contents of the area. If s is not NULL, it is assumed to be the address of an array of at least L_tmpnam bytes, where L_tmpnam is a constant defined through inclusion of <stdio.h>. The tmpnam() function places its result in that array and returns s. tmpnam_r() The tmpnam_r() function has the same functionality as tmpnam() except that if s is a null pointer, the function returns NULL. tempnam() The tempnam() function allows the user to control the choice of a directory. The argument dir points to the name of the directory in which the file is to be created. If dir is NULL or points to a string that is not a name for an appropriate directory, the path prefix defined as P_tmpdir in the <stdio.h> header is used. If that directory is not accessible, /tmp is used. If, however, the TMPDIR environment variable is set in the user's environment, its value is used as the temporary-file directory. Many applications prefer that temporary files have certain initial character sequences in their names. The pfx argument may be NULL or point to a string of up to five characters to be used as the initial characters of the temporary-file name. Upon successful completion, tempnam() uses malloc(3C) to allocate space for a string, puts the generated pathname in that space, and returns a pointer to it. The pointer is suitable for use in a subsequent call to free(). If tempnam() cannot return the expected result for any reason (for example, malloc() failed), or if none of the above-mentioned attempts to find an appropriate directory was successful, a null pointer is returned and errno is set to indicate the error. ERRORS
The tempnam() function will fail if: ENOMEM Insufficient storage space is available. USAGE
These functions generate a different file name each time they are called. Files created using these functions and either fopen(3C) or creat(2) are temporary only in the sense that they reside in a directory intended for temporary use, and their names are unique. It is the user's responsibility to remove the file when its use is ended. If called more than TMP_MAX (defined in <stdio.h>) times in a single process, these functions start recycling previously used names. Between the time a file name is created and the file is opened, it is possible for some other process to create a file with the same name. This can never happen if that other process is using these functions or mktemp(3C) and the file names are chosen to render duplication by other means unlikely. The tmpnam() function is safe to use in multithreaded applications because it employs thread-specific data if it is passed a NULL pointer. However, its use is discouraged. The tempnam() function is safe in multithreaded applications and should be used instead. When compiling multithreaded applications, the _REENTRANT flag must be defined on the compile line. This flag should be used only with multithreaded applications. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-------------------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-------------------------------------+ |Interface Stability |tmpnam() and tempnam() are Standard. | +-----------------------------+-------------------------------------+ |MT-Level |Safe | +-----------------------------+-------------------------------------+ SEE ALSO
creat(2), unlink(2), fopen(3C), free(3C), malloc(3C), mktemp(3C), mkstemp(3C), tmpfile(3C), attributes(5), standards(5) SunOS 5.10 18 May 2004 tmpnam(3C)