c - fscanf crashing while reading empty file -


i'm working on large project has function reads file of data. in test code however, file doesn't exist, , when it's created, creates empty text file. wrote following code compensate event:

typedef struct system_boot_status_s{   char timestamp[18];   int power_down_type;   int power_down_cause;   int boot_number;   int antenna_deployed;   int images_captured;   int beacon_count; }system_boot_status_t;  ////////////////////////////////  // read boot status info boot status struct   ret = fscanf(f, "%s %d %d %d %d %d %d",   bootstatus->timestamp,   bootstatus->power_down_type,   bootstatus->power_down_cause,   bootstatus->boot_number,   bootstatus->antenna_deployed,   bootstatus->images_captured,   bootstatus->beacon_count);    if (ret != 7) // if 7 items weren't read   {     // make sure boot status members set 0     snprintf(bootstatus->timestamp, boot_info_len, "xx-xx-xx-xx-xx-xx");     bootstatus->power_down_type = 0;     bootstatus->power_down_cause = 0;     bootstatus->boot_number = 0;     bootstatus->antenna_deployed = 0;     bootstatus->images_captured = 0;     bootstatus->beacon_count = 0;      return -1;   }

i know fscanf returns number of things reads, when run program , reaches empty file, program freezes. missing should doing eof? can me out?

arguments of fscanf (third , next) must pointers appropriate type. in simplest case can use & operator

hard problem, no automatic casting shorter int typed (char / byte)

ret = fscanf(f, "%s %d %d %d %d %d %d",   bootstatus->timestamp, // string   &bootstatus->power_down_type, // int ...   );

this depends on declaration, int declaration allowed in sample

if there not integers, use temporary variable. in example timestamp different kind of integral type (byte , on)

   int tmp1;      ret = fscanf(f, "%s %d %d %d %d %d %d",       bootstatus->timestamp,       &tmp1 ,     ...       );      bootstatus->power_down_type = tmp1;

breaking of rules give severe problems (depends on system, compilers etc)

my answer based on assumptions, not real declaration of structure, unknown @ moment of writing


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