TutFOpen

Name

TutFOpen — open a file in a platform-independent way

Synopsis

FILE *TutFOpen(file_name, file_mode) 
T_STR file_name; 
T_STR file_mode;

Arguments

file_name — name of file to be opened

file_mode — mode to open file in

Return Values

FILE pointer of opened file. NULL if unable to open file_name using file_mode.

Diagnostics

If TutFOpen fails, it returns NULL and sets the global SmartSockets error number to one of these values:

T_ERR_C — a C error has occurred. Call the function TutErrNumGetC to obtain the related C-specific error value.

T_ERR_NULL_PTR — either file_name or file_mode was NULL

Description

This function calls the C library function fopen using a standard set of arguments that opens a file in a "normal" way. This provides an operating system independent way to open a file. If called with the mode argument of "r", "w", or "a", then any necessary platform-specific arguments are added to make fopen behave with the expected UNIX semantics. On OpenVMS platforms, additional arguments are added to specify file sharing characteristics. The arguments expected for file_mode and their meanings are:

"r" — open file_name for reading. If file_name does not already exist, return NULL.

"w" — open for writing. If file_name already exists, it is overwritten. If it does not exist, create it.

"a" — open file_name for appending. If file_name does not exist, create it.

Any other value for file_mode causes the function fopen to be called with the specified argument.

Caution

Do not use this function to open a file with special arguments. If any special arguments are required, such as additional arguments that may be needed on OpenVMS, call fopen directly.

Examples

This example opens a file in write mode, truncating any previous contents of the file, and then writes one line of data into it:

FILE *file; 
 
file = TutFOpen("myfile.dat", "w"); 
if (file == NULL) { 
  /* error */ 
} 
 
fprintf(file, "%s", "This is a data file\n"); 
 
fclose(file);