Pass va_list or pointer to va_list?

by

It looks like you’ll need to pass a pointer to the va_list. For more info, see the C99 standard document section 7.15.In particular, bullet point 3 states:

The object ap may be passed as an argument to
another function; if that function invokes the va_arg macro with parameter ap, the
value of ap in the calling function is indeterminate and shall be passed to the va_end
macro prior to any further reference to ap

[my italics]

Edit: Just noticed a footnote in the standard:

215) It is permitted to create a pointer to a va_list and pass that pointer to another function, in which
case the original function may make further use of the original list after the other function returns

So you can pass a pointer to the va_list and do va_arg(*va_list_pointer) in the called function.

More Related Contents:

  1. Hash function for sorting 100 or more integar numbers [closed]
  2. Thread for Background Music
  3. Access element of array of pointer of structure
  4. pointer to string concept in c [closed]
  5. my code does not work and I don’t know why ;-;
  6. Pointer subtraction confusion
  7. Difference between a Structure and a Union
  8. Variable declaration placement in C
  9. Why does this implementation of offsetof() work?
  10. How do I check if a value matches a string
  11. Concatenating Variable Names in C?
  12. C Program crashes when adding an extra int
  13. How to get fractions in an integer division?
  14. C99 boolean data type?
  15. Freaky way of allocating two-dimensional array?
  16. How to print the address of a function?
  17. What does the statement if (counter & (1
  18. Socket accept – “Too many open files”
  19. How to find largest triangle in convex hull aside from brute force search
  20. Embedding HWND into external process using SetParent
  21. When can argv[0] have null?
  22. How to trap unaligned memory access?
  23. Empty structure in C
  24. Unexpected C/C++ bitwise shift operators outcome
  25. faster alternative to memcpy?
  26. log2 not found in my math.h?
  27. C programming – Loop until user inputs number scanf
  28. How to work with external libraries when cross compiling?
  29. Converting from Swift string to const char*
  30. Creating a FORTRAN interface to a C function that returns a char*

Leave a Comment