Tcl7.6 C API Man Page -- GetOpnFl (n)
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Tcl_GetOpenFile - Get a standard IO File * handle from a channel.


#include <tcl.h>

Tcl_GetOpenFile(interp, string, write, checkUsage, filePtr)


Tcl_Interp *interp (in) Tcl interpreter from which file handle is to be obtained.

*string (in) String identifying channel, such as stdin or file4.

write (in) Non-zero means the file will be used for writing, zero means it will be used for reading.

checkUsage (in) If non-zero, then an error will be generated if the file wasn't opened for the access indicated by write.

ClientData *filePtr (out) Points to word in which to store pointer to FILE structure for the file given by string.


Tcl_GetOpenFile takes as argument a file identifier of the form returned by the open command and returns at *filePtr a pointer to the FILE structure for the file. The write argument indicates whether the FILE pointer will be used for reading or writing. In some cases, such as a channel that connects to a pipeline of subprocesses, different FILE pointers will be returned for reading and writing. Tcl_GetOpenFile normally returns TCL_OK. If an error occurs in Tcl_GetOpenFile (e.g. string didn't make any sense or checkUsage was set and the file wasn't opened for the access specified by write) then TCL_ERROR is returned and interp >result will contain an error message. In the current implementation checkUsage is ignored and consistency checks are always performed.


channel, file handle, permissions, pipeline, read, write

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