Guardian C Library Calls Reference Manual

Reference to Library Calls
Guardian TNS C Library Calls Reference Manual—128833 3-139
perror
•
This function sets the file-position indicator to the start of the file (assuming that the
file is successfully opened).
•
For more information regarding file extents and pages, refer to the ENSCRIBE
Programmer’s Guide.
•
This manual does not include a discussion about waited I/O and nowait I/O because
the C programming language does not provide this capability. For waited and nowait
I/O, you must use Guardian system procedures.
Example
This example opens a file named $a.b.c for reading and writing:
#include <fcntlh>
int filedes;
filedes = open("$a.b.c", O_RDWR);
perror
The perror function prints the textual error message corresponding to the current value
of errno, optionally preceded by a specified string, to the standard error file, stderr.
user_text
points to a string or is the pointer value NULL.
Return Value
none.
Usage Guidelines
•
The form of the error message that perror prints is:
1. The string pointed to by user_text (if user_text is a nonnull pointer).
2. A textual message corresponding to the current value of errno. This message is
the same as the string strerror returns for the given value of errno.
3. A newline character.
#include <stdioh>
void perror(const char *user_text);