开始在MacOS上使用rocksdb

Question

我跟踪了指南，然后做了：

brew install rocksdb

而我却被困在这里。如何使用rocksdb？

我复制了此示例文件的内容并试图编译它，在Mac上使用gcc-5 (brew)和gcc (clang)，但它们都返回错误。我在MacOS10.11.5上使用Xcode 7.3.1。

错误是：

Undefined symbols for architecture x86_64:
  "_rocksdb_backup_engine_close", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_backup_engine_create_new_backup", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_backup_engine_open", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_backup_engine_restore_db_from_latest_backup", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_close", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_get", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_open", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_options_create", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_options_destroy", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_options_increase_parallelism", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_options_optimize_level_style_compaction", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_options_set_create_if_missing", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_put", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_readoptions_create", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_readoptions_destroy", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_restore_options_create", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_restore_options_destroy", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_writeoptions_create", referenced from:
      _main in ccNZ2cWh.o
  "_rocksdb_writeoptions_destroy", referenced from:
      _main in ccNZ2cWh.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status

更新：

将rocksdb库添加到Xcode中的头和库搜索路径后，如下所示：

​

​

我在rocksdb网站上试过

rocksdb::DB* db;
rocksdb::Options options;

并遇到了另一个问题：

​

​

Answer 1

您必须告诉链接器rocksdb库在哪里以及它的名称是什么，这样它才能找到符号。

假设自制将rocksdb安装到/usr/local/Cellar/rocksdb/4.5.1中，您可能需要如下所示：

gcc-5 -std=c++11 program.c -o program -L /usr/local/Cellar/rocksdb/4.5.1/lib -lrocksdb

或者，也许是一些不太特定于版本的东西，因为它无论如何都是符号关联的：

gcc-5 -std=c++11 program.c -o program -L /usr/local/lib -lrocksdb

如果您想使用Xcode GUI (而不是命令行)，您需要按照这个职位中的绿色、黄色、蓝色、红色的内容进行跟踪，但需要如上填写rocksdb的值。