In Fuerte, if a .cfg file used with dynamic_reconfigure contains a field named "i":
... gen.add( "i", double_t, SensorLevels.RECONFIGURE_RUNNING, "i gain", 1, 0, 200 ) ...the header will fail to compile with:
no match for ‘operator=’ in ‘i = boost::any_cast [with ValueType = double]((* & val))’The offending auto-generated code is:
class DEFAULT
{
public:
DEFAULT()
{
state = true;
name = "Default";
}
void setParams(PIDConfig &config, const std::vector params)
{
for (std::vector::const_iterator i = params.begin(); i != params.end(); i++)
{
boost::any val;
(*i)->getValue(config, val);
if("p"==(*i)->name){p = boost::any_cast(val);}
if("i"==(*i)->name){i = boost::any_cast(val);}
}
}
double p;
double i;
bool state;
std::string name;
}groups;
Here, it's clear that setParams is using an iterator called "i", yet a member variable "i" of type "double" also exists within the same class.
While the obvious solution is to change the config field name from "i" to something like "i_gain" in this particular case, this issue breaks diamondback-compatible code and limits the names which may be used for dynamic_reconfigure fields.
To clarify, I'm using Ubuntu 12.04 64-bit/gcc 4.6.3 on a VM with a clean ROS install and the latest updates installed via dist-upgrade.
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**Additional Issues**
It appears there are at least two more cases in which dynamic reconfigure param names can cause compilation issues.
When the class "DEFAULT" is added by the cfg generator:
class DEFAULT
{
public:
DEFAULT()
{
state = true;
name = "Default";
}
...
// variables from user-specified fields
...
// internal variables
bool state;
std::string name;
}groups;
the variables "state" and "name" appear to always be created, and will therefore conflict with any user-created variables with the same name.
To avoid these issues, it's probably a good idea to manually append "_param" or something similar to the name of all dynamic_reconfigure fields in .cfg files; however, as with the previous part of this issue, it would be great if this stuff would just work out-of-the-box.