gcc编译和运行hadoop c api程序
$ cat hdfs_cpp_demo.c// Following is a libhdfs sample adapted from the src/c++/libhdfs/hdfs_write.c of the Hadoop distribution.
#include "hdfs.h"
int main(int argc, char **argv) {
hdfsFS fs = hdfsConnect("master",9000);
if (!fs) {
fprintf(stderr, "Cannot connect to HDFS.\n");
exit(-1);
}
char* fileName = "demo_c.txt";
char* message = "Welcome to HDFS C API!!!";
int> int exists = hdfsExists(fs, fileName);
if (exists > -1) {
fprintf(stdout, "File %s exists!\n", fileName);
}else{
// Create and open file for writing
hdfsFile outFile = hdfsOpenFile(fs, fileName, O_WRONLY|O_CREAT, 0, 0, 0);
if (!outFile) {
fprintf(stderr, "Failed to open %s for writing!\n", fileName);
exit(-2);
}
// write to file
hdfsWrite(fs, outFile, (void*)message,> hdfsCloseFile(fs, outFile);
}
// Open file for reading
hdfsFile inFile = hdfsOpenFile(fs, fileName, O_RDONLY, 0, 0, 0);
if (!inFile) {
fprintf(stderr, "Failed to open %s for reading!\n", fileName);
exit(-2);
}
char* data = malloc(sizeof(char) *> // Read from file.
tSize readSize = hdfsRead(fs, inFile, (void*)data,> fprintf(stdout, "%s\n", data);
free(data);
hdfsCloseFile(fs, inFile);
hdfsDisconnect(fs);
return 0;
}
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