Porting UNIX Socket Applications to the SAS/C Environment

errno

When there is an error condition, most socket functions return a value of -1 and set errno to a symbolic value describing the nature of the error. The perror function prints a message that explains the error. The SAS/C Library adheres as closely as possible to symbolic UNIX errno values. However, programs may not receive exactly the same errno values as programs would in a particular implementation of the UNIX operating system. The message printed by the perror function may also differ.

Because errno is a macro and not a simple external variable, you should always declare it by including the <errno.h> header file.

Two external symbols, h_errno and _res , are defined parts of the network database and resolver interfaces. h_errno values are the same as those in common versions of the UNIX operating system, but the herror text may be different. As with errno , you cannot declare these symbols directly. Always declare them by including the appropriate header file.

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