C language functions

The z/TPFDF C language functions are set up in groups. All the functions in any one group perform a similar service.

For example, each function in the dfrst function group restores a subfile that you specify. The specific function in a group that you use depends on what parameters you want to specify. For example:
  • Use the dfrst function if you want to restore the current subfile.
  • Use the dfrst_acc function if you want to use an ordinal number, file address, or pointer to an algorithm argument to access the subfile.
  • Use the dfrst_seq function if you want to perform sequence number checking.
  • Use the dfrst_acc_seq function if you want to use an ordinal number, file address, or pointer to an algorithm argument to access the subfile, and perform sequence number checking.

The following topics contain an alphabetic listing of the z/TPFDF C language function groups that you can use in application programs. The description of each function group includes the following information:

  • Purpose: Describes how and why you use the function.
  • Last updated: Provides historical information about when the function was added, changed, obsoleted, or replaced.
  • Format: Provides the function prototype and a description of each parameter and variable.
  • Entry requirements: Lists any special conditions that must be true when you use the function.
  • Normal return: Lists what is returned when the function has completed processing successfully.
  • Error return: Lists what is returned when the function cannot complete processing successfully.
  • Programming considerations: Lists any additional considerations for using the function, including any restrictions or limitations.
  • Examples: Provides one or more examples that show you how to code the function.

Include the Correct Header Files

Code the following statement in all your z/TPFDF C language application programs: 
#include <cdf.h>
This statement causes all the necessary header files to be included in the C application program in the correct order. The following is a list of these header files:
  • c_cdfeq.h
  • c_cdfapi.h
  • c_cdfmac.h
  • c_cdflnk.h
  • c_cdferr.h
  • c_sw00sr.h
  • c_sw01sr.h
  • c_sw02sr.h

For information about the header files needed for z/TPF C support, see Application programming.