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SAS/C

The SAS/C® Tour


Performance Improvement

Tips

Following is a list of ways in which to improve the performance and efficiency of your SAS/C application.

  • If you use str*/mem* functions be sure to include string.h. If you call these functions many times, there is serious potential for a performance boost. Without it, you get normal function calls. With it, you get special built-in function calls.


  • Use compiler option reqproto to force you to include all headers for functions.


  • Create optimized code by using the optimize compiler option.


  • Look at using the __inline keyword to replace a call to the function with the code for the function itself. This could result in a significant improvement. Note: You must also use the optimize compiler option when using __inline.


  • Reduce the number of calls to user functions or look into inlining code. (See above.)


  • Efficient Programming Tips.


  • Use runtime option =usage to determine how STACK and HEAP storage is being used. Once this has been determined, changing initial allocation is a good potential for improvement and could even be significant.


  • The Inline Machine Code Interface enables a C program to generate supervisor calls (SVCs), DIAGNOSE instructions and CMS SVC 202s, and miscellaneous assembler language instructions that cannot normally be generated with a high-level language. This enables you to write more efficient code.


  • Choosing the correct Linkage Run-Time Options can make a significant difference in the amount of function overhead, how fast the program executes, and how easy it is to debug. Note that the linkage option =inter is the default.