if [ "x$GPGPUSIM_CONFIG" = "x" ];
时间: 2024-06-11 13:01:41 浏览: 138
if [ "x$GPGPUSIM_CONFIG" = "x" ] 是一个 Bash Shell 脚本中的条件语句,它的作用是判断环境变量 GPGPUSIM_CONFIG 是否为空。其中,"x" 是为了防止 GPGPUSIM_CONFIG 变量的值以 - 或者其他特殊字符开头而导致的问题。如果 GPGPUSIM_CONFIG 变量为空,则条件为真,执行 if 后面的语句块,否则跳过 if 后面的语句块。
相关问题:
1. Bash Shell 中的条件语句有哪些?
2. 什么是环境变量?
3. 如何设置环境变量?
相关问题
解释dir_y = dir_n = dir_ = dir_$(CONFIG_USER_802_1X) += 802.1x dir_$(CONFIG_USER_ACCEL_PPTP)
这是一个Makefile中的变量定义,其中包含了一个条件语句。该变量名为dir_y,初始值为空字符串;dir_n同样初始值为空字符串; dir_ 同样初始值为空字符串;dir_$(CONFIG_USER_802_1X)和dir_$(CONFIG_USER_ACCEL_PPTP)是两个条件语句,根据CONFIG_USER_802_1X和CONFIG_USER_ACCEL_PPTP的值来赋予相应的目录路径。比如,如果CONFIG_USER_802_1X被定义为y,则dir_y变量会被赋予802.1x目录路径;如果CONFIG_USER_ACCEL_PPTP被定义为y,则dir_y变量会被赋予对应的目录路径。这些变量的作用是在编译时根据条件编译的需要来决定是否编译相应的目录。
给下列程序添加注释: void DWAPlannerROS::reconfigureCB(DWAPlannerConfig &config, uint32_t level) { if (setup_ && config.restore_defaults) { config = default_config_; config.restore_defaults = false; } if ( ! setup_) { default_config_ = config; setup_ = true; } // update generic local planner params base_local_planner::LocalPlannerLimits limits; limits.max_vel_trans = config.max_vel_trans; limits.min_vel_trans = config.min_vel_trans; limits.max_vel_x = config.max_vel_x; limits.min_vel_x = config.min_vel_x; limits.max_vel_y = config.max_vel_y; limits.min_vel_y = config.min_vel_y; limits.max_vel_theta = config.max_vel_theta; limits.min_vel_theta = config.min_vel_theta; limits.acc_lim_x = config.acc_lim_x; limits.acc_lim_y = config.acc_lim_y; limits.acc_lim_theta = config.acc_lim_theta; limits.acc_lim_trans = config.acc_lim_trans; limits.xy_goal_tolerance = config.xy_goal_tolerance; limits.yaw_goal_tolerance = config.yaw_goal_tolerance; limits.prune_plan = config.prune_plan; limits.trans_stopped_vel = config.trans_stopped_vel; limits.theta_stopped_vel = config.theta_stopped_vel; planner_util_.reconfigureCB(limits, config.restore_defaults); // update dwa specific configuration dp_->reconfigure(config); }
/**
* @brief Callback function for dynamic reconfiguration of DWA planner parameters
*
* @param config Reference to the configuration object that stores the updated parameters
* @param level The level of reconfiguration, unused in this function
*/
void DWAPlannerROS::reconfigureCB(DWAPlannerConfig &config, uint32_t level) {
// If the setup has been completed and restore_defaults flag is set, restore default configuration
if (setup_ && config.restore_defaults) {
config = default_config_;
config.restore_defaults = false;
}
// If setup has not been completed, store default configuration and set the setup flag to true
if ( ! setup_) {
default_config_ = config;
setup_ = true;
}
// Update generic local planner parameters
base_local_planner::LocalPlannerLimits limits;
limits.max_vel_trans = config.max_vel_trans;
limits.min_vel_trans = config.min_vel_trans;
limits.max_vel_x = config.max_vel_x;
limits.min_vel_x = config.min_vel_x;
limits.max_vel_y = config.max_vel_y;
limits.min_vel_y = config.min_vel_y;
limits.max_vel_theta = config.max_vel_theta;
limits.min_vel_theta = config.min_vel_theta;
limits.acc_lim_x = config.acc_lim_x;
limits.acc_lim_y = config.acc_lim_y;
limits.acc_lim_theta = config.acc_lim_theta;
limits.acc_lim_trans = config.acc_lim_trans;
limits.xy_goal_tolerance = config.xy_goal_tolerance;
limits.yaw_goal_tolerance = config.yaw_goal_tolerance;
limits.prune_plan = config.prune_plan;
limits.trans_stopped_vel = config.trans_stopped_vel;
limits.theta_stopped_vel = config.theta_stopped_vel;
// Call reconfigureCB function of the planner_util_ object with updated limits and restore_defaults flag
planner_util_.reconfigureCB(limits, config.restore_defaults);
// Call reconfigure function of the dp_ object with updated configuration
dp_->reconfigure(config);
}