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  1. #include <stdio.h>
  2. #include <stddef.h>
  3. #include <stdlib.h>
  4. #include <stdbool.h>
  5. #include <assert.h>
  6.  
  7. #define allocate( type, n ) malloc( sizeof(type) * n )
  8. #define clear_allocate( type, n ) calloc( n, sizeof(type) )
  9.  
  10. // total rows initialized in pool
  11. #define NUM_ROWS (size_t)100
  12.  
  13. #define HEIGHT (size_t)3
  14. #define WIDTH (size_t)4
  15.  
  16. int main() {
  17.  
  18.     typedef double Element;
  19.     typedef Element* Row;
  20.     typedef Row* Matrix;
  21.  
  22.     _Bool allocate_successfully = true;
  23.     size_t failure_at = NUM_ROWS;
  24.  
  25.     // handle of all rows
  26.     Row * allocated_rows = allocate( Row, NUM_ROWS );
  27.     assert( allocated_rows != NULL ); // fatal error
  28.     // init each rows ( allocate memory needed )
  29.     for ( size_t i = 0; allocate_successfully && i != NUM_ROWS; ++i ) {
  30.  
  31.         allocated_rows[ i ] = allocate( Element, WIDTH );
  32.  
  33.         if ( allocated_rows[ i ] == NULL ) {
  34.             allocate_successfully = false;
  35.             failure_at = i;
  36.         }
  37.     }
  38.  
  39.     if ( allocate_successfully == false )
  40.         goto after_use;
  41.  
  42.     size_t next = 0;
  43.     Matrix a1 = allocate( Row, HEIGHT );
  44.     assert( a1 != NULL ); // fatal error
  45.     for ( size_t row = 0; row != HEIGHT; ++row ) {
  46.         a1[ row ] = allocated_rows[ next++ ];
  47.     }
  48.  
  49.     Matrix a2 = allocate( Row, HEIGHT );
  50.     assert( a2 != NULL ); // fatal error
  51.     for ( size_t row = 0; row != HEIGHT; ++row ) {
  52.         a2[ row ] = allocated_rows[ next++ ];
  53.     }
  54.  
  55. after_use:
  56.     {
  57.     Matrix matrices[] = { a1, a2 };
  58.     for ( size_t i = 0; i != sizeof(matrices)/sizeof(matrices[0]); ++i )
  59.         free( matrices[ i ] );
  60.  
  61.     // free the rows allocated in pool
  62.     for ( size_t i = 0; i != failure_at; ++i )
  63.         free( allocated_rows[ i ] );
  64.     free( allocated_rows );
  65.     }
  66.  
  67.     return EXIT_SUCCESS;
  68. }
Success #stdin #stdout 0.02s 1848KB
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https://ideone.com/IWKiYe
language:
C99 (gcc 8.3)
created:
12 years ago
visibility:
public

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