Guardian Native C Library Calls Reference Manual (G06.28+, H06.04+)

Guardian Native C Library Calls (f) fopen_guardian(3)
Explicit calls to the fopen_oss() and fopen_guardian() variants in source code are only made
when the behavior of one environment is desired from the other environment.
fopen_oss( ) is functionally identical to the fopen( ) function of the OSS environment. It is the
same as setting systype oss at compile-time. systype oss is the default setting for c89 in
the OSS environment and on UNIX workstations.
fopen_guardian() is functionally identical to the fopen( ) function of the Guardian environment.
It is the same as setting systype guardian at compile-time. systype guardian is the
default setting for the C and C++ compilers in the Guardian environment.
To use the fopen_oss() or fopen_guardian() functions, specify the _TANDEM_SOURCE
feature test macro.
RETURN VALUES
If the fopen() function succeeds, a pointer to the stream is returned. If the fopen() function fails,
a null pointer is returned, and errno is set to indicate the error.
ERRORS
If any of the following conditions occurs, the fopen() function sets errno to the value that
corresponds to the condition.
[EINVAL] The mode parameter is not a valid mode.
[EMFILE] The OPEN_MAX file descriptors are currently open in the calling process.
[ENFILE] Too many files are currently open in the processor.
[ENOENT] The named file does not exist or the filename parameter points to an empty
string.
[ENOMEM] Insufficient space to allocate a buffer.
For all other error conditions, errno is set to the appropriate Guardian file-system error number.
Refer to the Guardian Procedure Errors and Messages Manual for more information about a
specific Guardian file-system error.
RELATED INFORMATION
Functions: open(2), fclose(3), fopen(3), fopen_oss(3), freopen(3), fseek(3), setbuf(3).
STANDARDS CONFORMANCE
The fopen_guardian() function is an HP extension to the XPG4 Version 2 specification.
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