Python load C library

1. create a dynamic link library:
　　　　    gcc -shared -fPIC -o share_lib.so share_lib.c

2. the use of a .so:
    　　gcc main.c ./share_lib.so -o main

 

main.c:

#include <stdio.h>

int main(int argc, char *argv[])
{
    int array[5] = {5, 4, 3, 2, 1};
    int item;
    int pos;
    insert_sort(array, 5);
    printf("please input a number\n");
    scanf("%d", &item);
    pos = binary_search(array, item, 5);
    if(pos == -1){
        printf("cant't find\n");
    }else{
        printf("the position is %d\n", pos+1);
    }
    return 0;
}

 

share_lib.c:

// insert sort function
void insert_sort(int *array, int length)
{
    int i, j;
    for(i = 0; i < length; ++i){
        int temp;
        j = i;
        temp = array[i];
        while(j > 0){
            if(temp < array[j - 1]){
                array[j] = array[j - 1];
                --j;
            }else{
                break;
            }
        }
        array[j] = temp;
    }
}
// binary search
int binary_search(int *array, int item, int length)
{
    int high, low, mid;
    high = length - 1;
    low = 0;
    mid = (high + low) / 2;
    while(low < high){
        if(array[mid] > item){
            high = mid;
            mid = (high + low) / 2;
        }else if(array[mid] < item){
            low = mid;
            if( (high + low) % 2 == 0)
                mid = (high + low) / 2;
            else
                mid = (high + low)/2 + 1;
        }else
            return mid;
    }
    return -1;
}

void bubble_sort(int *array, int length)
{
    int i, j;
    int exchange = 1;
    i = 0;
    int temp;

    while(i < length && exchange){
        j = length - 1;
        exchange = 0;
        while( j > i){
            if(array[j] < array[j - 1]){
                temp = array[j];
                array[j] = array[j - 1];
                array[j - 1] = temp;
                exchange = 1;
            }
            --j;
        }
        i++;
    }
}

 

python call *.so:

    #! /usr/bin/python
    from ctypes import *
    import os

    libtest = cdll.LoadLibrary(os.getcwd() + '/share_lib.so')

    TenIntArrayType = c_int * 10;

    arr = TenIntArrayType(10, 9, 8, 7, 6, 5, 4, 3, 2, 1)
    #for i in xrange(10):
    #    arr[i] = 10 - i

    libtest.insert_sort(pointer(arr), 10)
    print libtest.binary_search(pointer(arr), 3, 10)

 

 

 pack multiple .c files to one .so:
    　　gcc -Wall -fPIC -c *.o
    　　gcc -shared -o so_name *.o