[HDFS-14394] Add -std=c99 / -std=gnu99 to libhdfs compile flags

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.3.0, 3.2.2
• Component/s: hdfs-client, libhdfs, native
• Hadoop Flags: Reviewed
• Assignee: Sahil Takiar
• Reporter: Sahil Takiar
• Created: 28/Mar/19 00:05
• Updated: 11/Aug/20 07:47
• Resolved: 03/Apr/19 18:01

Description

libhdfs compilation currently does not enforce a minimum required C version. As of today, the libhdfs build on Hadoop QA works, but when built on a machine with an outdated gcc / cc version where C89 is the default, compilation fails due to errors such as:

/build/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/jclasses.c:106:5: error: ‘for’ loop initial declarations are only allowed in C99 mode
for (int i = 0; i < numCachedClasses; i++) {
^
/build/hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/jclasses.c:106:5: note: use option -std=c99 or -std=gnu99 to compile your code

We should add the -std=c99 / -std=gnu99 flags to libhdfs compilation so that we can enforce C99 as the minimum required version.

Issue Links

• relates to: HADOOP-17196 Fix C/C++ standard warnings
• relates to: HADOOP-16236 Update C code to run with c99 standard