printf format specifiers for uint32 t and size t

Question

I have the following  size t   i   0  uint32 t k   0   printf  i    lu   k    u   n   i  k     I get the following warning when compiling   format     lu    expects type    long unsigned int     but argument has type    uint32 t      When I ran this using splint I got the following   Format argument 1 to printf   u  expects unsigned int gets size t  k   Many thanks for any advice

User · Accepted Answer

Sounds like you re expecting size t to be the same as unsigned long  possibly 64 bits  when it s actually an unsigned int  32 bits   Try using  zu in both cases   I m not entirely certain though

User · Answer

If you don t want to use the PRI  macros  another approach for printing ANY integer type is to cast to intmax t or uintmax t and use   jd  or  ju  respectively  This is especially useful for POSIX  or other OS  types that don t have PRI  macros defined  for instance off t

User · Answer

All that s needed is that the format specifiers and the types agree  and you can always cast to make that true  long is at least 32 bits  so  lu together with  unsigned long k is always correct   uint32 t k  printf   lu n    unsigned long k     size t is trickier  which is why  zu was added in C99  If you can t use that  then treat it just like k  long is the biggest type in C89  size t is very unlikely to be larger    size t sz  printf   zu n   sz       C99 version    printf   lu n    unsigned long sz       common C89 version      If you don t get the format specifiers correct for the type you are passing  then printf will do the equivalent of reading too much or too little memory out of the array  As long as you use explicit casts to match up types  it s portable

User · Answer

Try   include  lt inttypes h gt       printf  i    zu   k     PRIu32    n   i  k     The z represents an integer of length same as size t  and the PRIu32 macro  defined in the C99 header inttypes h  represents an unsigned 32-bit integer

[c] printf format specifiers for uint32_t and size_t

Examples related to c

Examples related to printf